Measurement of I Radioactivity in Groundwater of Radioactive Waste Disposal Site

The investigation of the environmental radioactivity around the radioactive waste disposal site in Gyeongju is being carried out. The radioactivity of I in groundwater and seaweed are to be measured. The analytical method to measure the radioactivity of I in aqueous media was established. This method contains oxidation-reduction reaction, anion-exchange separation and palladium precipitation. The I radioactivity in the PdI2 precipitates was measured by using low-energy gamma spectrometer. The counts of peak at 39.6 keV of gamma energy were used for determination of I radioactivity. The chemical recovery was determined by the weights of PdI2 precipitates. The deionized water and groundwater spiked with I tracer were tested. In the case of deionized water, the relative deviations of measured concentration from spiked one are from 1.1 to 10.7%. The relative deviations of measured radioactivity from spiked one in the groundwater experiments are 2.9 and 3.7%. The measured concentration is in good agreement with spiked one. The groundwater sampled from radioactive waste disposal site was tested. The concentrations of I in the groundwater are below minimum detectable activities of 36.7 and 36.6 mBq/L.